1. Field of the Invention
The present invention relates to a soft-start circuit to be provided in a switching power supply apparatus, such as a DC-DC converter.
2. Description of the Related Art
The switching power supply apparatus, such as a DC-DC converter, generally includes an error amplifier for comparing an output voltage with a reference voltage, being configured so as to control the switching operation in accordance with the output of the error amplifier, and is provided with a soft-start circuit for gradually raising the reference voltage to be compared with the output voltage at power-up (for example, Patent Document 1). By providing a soft-start circuit, it is made possible to prevent the output of the DC-DC converter from overshooting due to a rush current into a load at power-up, or to adjust the soft-start time for establishing the order of starting with respect to the other ICs loaded on the same power supply substrate.